hdu1556-Color the ball

题目链接 http://bak.vjudge.net/problem/HDU-1556

解题思路

直接线段树。

代码

#include<stdio.h>
#include<string.h>
#define MAX_SIZE 100010
//#define LOCAL
struct node {
    int left, right;
    int count;
}tree[MAX_SIZE*4];
int now;
int n;
void build(int l, int r, int root)
{
    tree[root].left = l;
    tree[root].right = r;
    tree[root].count = 0;
    if(l == r) return;
    int mid = (l + r) / 2;
    build(l, mid, root*2);
    build(mid+1, r, root*2+1);
}
void update(int l, int r, int root)
{
    if(tree[root].left == l && r == tree[root].right) {
        tree[root].count++;
        return ;
    }
    if(tree[root].count != 0) {
        tree[2*root].count += tree[root].count;
        tree[2*root+1].count += tree[root].count;
        tree[root].count = 0;
    }
    int mid = (tree[root].left + tree[root].right) / 2;
    if(r <= mid) update(l, r, root*2);
    else if(mid < l) update(l, r, root*2+1);
    else {
        update(l, mid, root*2);
        update(mid+1, r, root*2+1);
    }
}
void cal(int root)
{
    if(tree[root].left == tree[root].right) {
        if(now != n) printf("%d ", tree[root].count);
        else printf("%d\n", tree[root].count);
        now++;
        return ;
    }
    if(tree[root].count != 0) {
        tree[2*root].count += tree[root].count;
        tree[2*root+1].count += tree[root].count;
        tree[root].count = 0;
    }
    cal(root*2);
    cal(root*2+1);
}
int main()
{
    #ifdef LOCAL
        freopen("ans.txt", "w", stdout);
    #endif
    scanf("%d", &n);
    while(n != 0) {
        build(1, n, 1);
        int x, y;
        now = 1;
        for(int i=0; i<n; i++) {
            scanf("%d%d", &x, &y);
            update(x, y, 1);
        }
        cal(1);
        scanf("%d", &n);
    }
    return 0;
}